The density of a solution prepared by dissolving 120g of urea (mol. Mass=60u) in 1000g of water is 1.15 `g*mL^(-1)`. The molarity of this solution is-

Options

A. 1.78M
B. 1.02M
C. 2.05M
D. 0.50M

Answer

C

Explanation

Mass of solute=120g, molecular mass of solute=60u
Mass of solvent=1000g, Density of solution=`1.15g*mL^(-1)`
Total mass of solution`=1000+120=1120`g
Volume of solution`=(mass)/("density")=(1120)/(1.15)mL`
Molarity`=(("mass of solute")/("molecular mass of solute"))/("volume of solution")xx1000`
`=(120xx60)/(1120//1.15)xx1000=(2xx1000xx1.15)/(1120)=2.05(M)`